Docker Container: Postfix Configuration | "Main.Cf" resets port on relayhost

Dear Community,

i have a docker container running on docker desktop for Windows 10.
As i was configuring the postfix i restarted the client and after that i didn't get any new mails.
I was checking the "" file, but then i found out, that the Variable Relayhost.PNG changed to
Relayhost new.PNG ????
Other variables didn't change in the file...

Now i have to manually change it every time when restarting the container. (other variables didn't change.)

So my question is:
Is there any way, that this variable doesn't change after restarting the client?